The present invention is directed to additional embodiments of clinch nuts such as those described and claimed in U.S. patent application Ser. No. 118,300 (hereinafter the '300 application). More particularly, the present invention is directed to sheet metal clinch nuts particularly adapted for being secured to plastic panels and the like. Because of the relationship between the '300 application and the present application, the former application is hereby incorporated by reference.
While the '300 application clinch nut is for attachment and use with thin metal panels, the clinch nut of the present invention is for thin plastic panels. An example where the clinch nut of the present invention can be particularly suited for use is in the liners for refrigerators. The interior liner or wall of the refrigerator is a one piece plastic member which can be vacuum formed, for example. The liner is inserted and attached to the refrigerator casing and then insulation is foamed-in-place between the inner and outer walls. Subsequently, shelf and drawer supports, light fixtures and other accessories must be affixed to the interior of the liner. Some type of metal fastening member is necessary to backup the plastic so as to distribute the load and prevent the fastener from pulling out of the plastic.
Conventional clinch nuts, and even those of the '300 application, require the panel to be punctured to effect attachment to the panel. Such throughbores are clearly undesirable in an application such as this, since the foamed insulation would seep through these holes in the refrigerator compartment and not be retained between the two walls.
The present invention overcomes these deficiencies in prior art clinch nuts by providing an inexpensive, sheet metal nut which can be affixed to a thin plastic panel without the need for piercing the plastic. The clinch nut of the present invention has an aperture and a recess particularly adapted to receive an extruded portion of the plastic panel and retain the nut against axial and rotational displacement with respect to the panel. The aperture is configured such that the panel need not be punctured, which makes it especially useful in applications such as that previously noted. Novel methods of staking a clinch nut to a plastic panel and installing the lead nut of a continuous strip of clinch nuts are also disclosed.
Various other features, objects and advantages of the present invention will become apparent following a reading of the following detailed description when taken in conjunction with the accompanying drawings.